1. Field of the Invention
The present invention relates to a die apparatus and a die exchanging method in a pressing machine.
2. Description of the Prior Art
A die apparatus in a pressing machine comprises a lower die unit in which a lower die set containing lower die members is received in a lower die holder and an upper die unit in which an upper die set containing upper die members is received in an upper die holder. And, with the lower and upper die holders securely fixed to a lower and an upper die plate, respectively, which are in turn securely fixed to a bolster and a slide, respectively, the lower and upper die units are securely held by the bolster and the slide, respectively.
An existing die apparatus of this type, in which the lower and upper die units are each dealt with as an assembly, has been so designed that when the lower and upper dies are each exchanged, the lower and upper die units each with its die holder must wholly be removed from the bolster and slide, respectively, and in the outside of the machine each of the lower and upper dies must, by means of a chain hoist or the like, be extracted upwards from the die holder, together with a plate in which it is circumferentially fitted and must then be decomposed.
Thus, in the conventional die apparatus, since it is necessary to remove two such die units together with their respective die holders into the machine's outside each time a lower and an upper die are exchanged and further to extract upwards each of the lower and upper dies from its die holder, together with a plate in which it is circumferentially fitted, respectively, there has been encountered the problem that quite a time-consuming die exchanging operation is required.